Continuous aftertreatment of rayon



June 1950 H. A. SCHRENK commuous AFTERTREATMENT 0F RAYON Filed Dec. 4.1946 FROM 1 filaments are in thebaths.

Patente'cl June 27, 1950 UNITED; STATES PATENT OFFICE CONTI NUOUSAFTERTREATMENT OF RAYON Hans Alwin Schrenk, Arnhem, Netherlands,assignor to American Enka Corporation, Erika, N. 0., a corporation ofDelaware Application December 4, 1946, Serial No. 713,905 In GermanyJuly 14, 1941 Section 1, Public Law 690, August 8, 1946 Patent expiresJuly 14, 1961 1 Claim.

This invention relates to the treatment of rayon and is moreparticularly concerned with a method and apparatus for the continuouswet treatment of a plurality of rayon yarns'moving between a point ofextrusion and a point of col-- lection.

1 In the aftertreatment of rayon yarns, each composed of a multiplicityof filaments, it is known to pass the same in a continuous operationthrough a series of treating tanks wherein the yarns are guided beneaththe surface of liquid in each tank and parallel to the surface thereof.Two types of guiding rollers are normally employed for this purpose, onetype being located above the tanks for guiding-the yarns from one tankto the other, and the other type being wholly or partially immersed inthe liquid of the tanks for guiding the yarns through the treatingbaths.

It has now been determined that it'is not necessary to drive all of therollers, because if the rollers located above the tanks are driven, therollers immersed in the baths can be freely rotatableas the yarnspassing thereover will rotate the same. In order to maintain the yarnsin parallel relationship during their passage through v the baths, it ispreferable to provide the rollers above the baths with parallel grooves,whereas the rollers immersed in the baths can have a smooth surface.

In the foregoing process, it is necessary that;

the individual filaments should not be separated too much because thenthe filaments of the adjacent, moving yarns may become entangled.

The separation of the filaments is dependent upon the distance theytravel through the bath, the speed at which they travel through the bathand the tension on the filaments which has been imposed in front of thefirst roller.

It is therefore an object of this invention to overcome the foregoingdifficulties and to provide a method and apparatus for theaftertreatment of multi-filament rayon yarns wherein the yarns aresubjected to adequate aftertreatment in passage through baths ofrelatively short physical length.

It is contemplated, according to this invention, to separate thecomponent filaments of a yarn so as to cause the yarn to assume ribbonform during its passage through an aftertreatment bath, whereby theindividual filaments may be On the other hand,

I travel through liquid I2.

2 better contacted with the aftertreating liquid.

It is a further object of this invention to provide apparatus forfeeding yarn to, and withdrawing yarn from, baths of aftertreating.liquid in such manner that the threads will be properly spread intoribbon form in theirpassage through the aftertreating liquid in order toeffect sufficient penetration of the treating liquid withoutentanglement.

Other objects and advantages of this invention will be apparent uponconsideration of the following detailed description of a preferredembodiment thereof in conjunction with the annexed drawings wherein: I

Figure 1 is a diagrammatic view in vertical section of apparatusconstructed in accordance with the present invention; and

Figure 2 is a fragmentary view in plan illustrating a typical drivingconnection for the apparatus shown in Figure 1.

Referring now in greater detail to Figure 1, the numerals II), II and I2designate containers for the reception of aftertreating liquids I3, I4and I5 which may be water, sodium sulphide and water respectively. Theyarn issuing from a spinning position, not shown, is delivered to thecontainer III by a driven roller I6. The yarn passes from driven rollerI6 through aftertreating liquid l3. In container I0 there are locatedtwo freely rotatable guiding rollers I1 and I 8 around which the threadpasses in its path of From the roller I8 the yarn is withdrawn from thecontainer I tl by a driven roller I9 and roller I9, in addition toWithdrawing the yarn from the container I0, also feeds it into containerI I. In passing through container II the yarn is guided by rollers 20and 2| corresponding in structure and function to rollers I! and I8. Theyarn is withdrawn from the container I I by a driven roller 22corresponding in structure and function to the roller IS. The apparatusfor guiding the yarn through the container I2 corresponds to thatdescribed in connection with container II and includes freely with bevelgears 30, 3| and 32 respectively to drive rollers I9, 22 and 25respectively, all at the same speed. Shaft 26 also provided with .abevel gear 33 whichzmeshes with a bevel gear 34 which drives one side ofa change speed transmission 35 of any conventional design such as, forexample, a P. I. V. transmission which is a, standard link belt variablespeed drive mechanism. The letters P. I. V. stand for positiveinfinitely variable. The output side of the transmission 35 is "thatare" possible within the scope of the invenconnected through a shaft 36to the driven-roll- It has been discovered, as an important part, ofthis invention, that if the roller which feeds the yarn to theafter-treating liquid is driven at a different speed from the rollerswhich withdraw the yarn from that liquid, it is possible to control thedegree of separation of the component fila- .ments of the yarn in such away as to best expose them for reaction with the after-treating liquid.

It is for this re son that the transmission 35 is provided, for bythe-us'eof this transmission, it

is possible tO diiVe th roller lfi at a s'p'e'ed which I is differentfrom the speeds of rollers 19, 22 and "'25; The range ofvariationbetween the speed of roller 16 and the speedof the otherrollers can brewery small. It is found that upon increase in the speedof the roller 16 relative to the other rollers, filament separation isincreased while a decrease in the speed of the roller 16' relative 'tothe other rollers, results inadecrease in filamenu separation. "Thephenomenon or filament separationo'f-thesort described is'not fullyunderstood, but is believed to result from the elasticity of the wetthreads.

Tests have shown that adequate'filament separation in all of thetreating baths I3, 14 and 15 will be attained, for example, if each bathis 45 (if slifi'icient axial length SO 'that a plurality of yarns movingin parallel relationship may be accommodated thereby for simultaneousaftertreatment.

It can now be seen'that by practicing the method here disclosedandbyusing the apparatus here described, it is possible to adequately controlfilament separation in the passage of freshly spun yarns throughaftertreatin'g baths with the re- 'tion.

-What is claimed is:

-A-;metho d -of=-aftertreating freshly spun substantially untwistedmulti-filament rayon yarns which comprises feeding a plurality of suchyarns "continuously in parallel relationship into a stationary, commonbath at a, constant speed, passingkthe yarns from said bath and into,through and out of additional stationary and common I draws-1 from the'last baths while maintaining the yarns out of contact with each otherand exposed on all sides to the bath liquid and in parallel relation toeach other, withdrawing the yarns [from the last bath at a-cons'tantspeed lower than the speed of I delivery thereof to the-first bath, andapplyinga uniform propulsive foree to eaeh of the yarns between adjacent-baths under slippage permissive conditions, the propulsive forceapplied to the yarns between the respective baths being at substantiallythesame speed a'sthe rate of yarn with- V th, whereby the yarns' arepassed tm'o igh at i'least'some of the baths at a rate greater thantl'lerateof application df propulsive force thereto with resultant adjustmentof the individual yarns due to inherent shrinkage and slip with respecttthe propulsive force applied thereto and resultant passage of the yarnsthrough the'baths in re1axed condition that Number Name Date 580,636Burrows Apr. 13, 1897 1,971,627 Stuhlmann et a1. 'Aug.-28, 19342,066,168 Witte Dec. 29,1936 2,203,375 Weiss JuneA, 1940 2,239,636 Weiss-Apr.22; 1941 2,251,931 Gundelfinger 2 Aug. 12,1941 2,267,117 "Mann Dec.23,1941 2,276,605

, Andrews"; -s Mar. 17,- 1942

